Chromable dyestuffs and a process of making same



Patented Oct. 14, 1947 CHROMABLEDYESTUFFS' 'AND" A PROCESS.

OF MAKING SAME Achille Gonzet'ti and Guido Schetty, Basel, and Otto Schmid, Muttenz, Switzerland; assignors Switzerland, a Swiss firm.

to: J. R; Geigy, Basel,

No Drawing. Application May 1, 1944-, Serial No. 533,660. In SwitzerlandJ'uned, 1943 15 Claims. 1

It is well known totransform dyestuffs, which are capable of being chromed and contain sulfonic acid groups, into the corresponding chromium complex compounds by heating the said dyestuffs with chromium compounds in the presence of water or of other solvents.

We have now found that it is possible to produce new, valuable, chromium-containing dyestuffs in substance by using chromium complex compounds of o-hydroxy carboxylic' acids ofthe benzene series for the purpose of chroming ch'romable dyestuffs containing sulfonic acids.

As starting materials for the chromium complex compounds in accordance with the invention use may be made of o-hydroxybenzoic acid, its homologues and substitution products, such as for instance 2-hydroxy-3-, -4- or 5-methylbenzoic acid, 2-hydroxy-5-chlorobenzoic acid, 2.- hydroxy-l-benzoic acid-5-su1f'onic acid, their derivatives like for example 2-hydroxy-1-benzoic acid 5 sulfethyl anilide, 2-hydroxy-1-benzoic acid 5 sulfonic'acid-phenylor -o-to1yl ester;

moreover, 4-p-toluene sulfamino-salicylic acid, 2-

hydroxy-S-phenoxybenzoic acid, etc., may also be used. The preparation of the chromium complex compounds is carried out according tousual methods, cf. e. g. Barbieri, R; A. L. (5) 241.608.

When chroming with the chromium complex compounds of o-hydroxy carboxylic acid. of. the benzene series there has surprisingly been. observed that in many cases the chroming takes place in a much more rapid and. smoother manner than when working according to the chroming methods known hitherto, i. e. by means of. chromium salts, chromites, chromium compounds with auxiliary agents like for instance oxalic acid, salicylic acid, sulfosalicyclic acid and so on. In 'lnany cases dyestufi complex compounds can be produced within a short time according to the nvention, whereas the known ch'romingmethods iequire incomparably longer reaction periods or the working under pressure at temperaturesabove 100 C. Since the chroming in accordance with the invention can be carried out in a neutral reaction medium, this method allows. ingeneral the chroming of dyestufis containing groups which are sensitive to alkalis or acids, without changing these groups which, according to the constitution of the dyestuff to be chromed, are. of decisive importance for the fastness properties or the levelling power of the. complex dyestufi. Of course, in the literature also. chroming. agents have become known which react only slightly acid or even neutral, so that the sameleave intact such sensitive groups. Thus, for example,

. 2: the chroming: with" chromium: oxide hydrate pastes or with chromium salts of weak organic carboxylic acidslike chromium acetate may be mentioned; Itisia known fact, that, when workingwith thesaidr chromium compoundsgeneral- 'ly the chromi'ng according to usual methods is notsu'ccessiulwith o o. -dihydroxyor-o-hydroxyo. -carboxy azodyestuiis containing only-one solubilising group; In such cases it is mostly necessary" to: use diluents, in: a disproportionate ratio in order to: guarantee the chromation, whereby thismethod. of working'becomes uneconomic.

It. is known that chromium-containing, wool dyestuffs :may be dyed-in. an optimalmanner from relatively weakly acid bathsan'd-preferably from organic acid baths (compare Ender andMiiller, Melliands Textilberichte 193.8, pages 65, 81 and 2'72). However, apart from some exceptions, such dyeings obtained with. the chromium containing dyestu-fis known hitherto are worthless, since theirsliadesarenot yet". completely developed and theygive'uneven dyeings onifabrics, so that the same have askittery appearance. Only from a mineral'acidbath (there has been proposed: to add 8-1O%'-suliur'ic.acid calculated with reference to the dyeing goods) theknown chromium. complex dyestufis. yield as'arule practically useful, beautiful and. even: dyeings-whi'chhave been de' veloped only by'the strongacid dyeing. Moreover, theidyeings obtainable from: an organic acid bath often. possess inferior fastness' properties than the dyeings resulting from a mineral acid bath. In contradistinction thereto the chromium complex dyestuffs of the present invention have the surprising and remarkable properties that they dyewool from a slightly mineral acid bath, e. g. from a 1':%* sulfuric acidbath, or more preferably' from an organic acid bath, e. g. from a 2 -4 %-iormicacidr'bath, in full and even shades of excellent fastness properties without change of shades, whereas dyestuffs chromed according to hitherto known. methods. only obtain their full coloring properties on. dyeing or developing respectively with a relatively'high'percentage of mineral acid.

These important properties of the new chromium-containing dyestuffs consistingin that they yield from an organic acid dyeingbathsatisfactory dyeings create: for the dyestufi chromium complex compounds new possibilities of application, which were not accessible hitherto for most of the known. metallised dyestufis'in view of the high acid concentration required for dyeing. 'Asr'such possibilities may, be 1 mentioned for instance: the semi-wool dyeing. or the dyeing of Example 1 ing for the greatest part still insoluble at the be-' ginning of the chromin becomes dissolved within to minutes to. a deep blue coloration under formation of the complex compound. The complex dyestuff is isolated by addition of sodium chloride and the product thus precipitated in a sandy form is dried. The dyestuff, a deep blue powder, is easily soluble in water and dyes wool from a formic acid bath in flowery blue shades of very good uniformity. The so-obtained dyeings possess very good fastness properties to light, to rubbing and in the moist state.

Example 2.

28.1 parts of the dyestufi from diazotised 4- chloraminophenol and 1:8 -naphtholsulfonic acid-3-sulfethylanilide are stirred in 1500 parts of water and boiled under reflux for several hours with 140 parts of a solution of ammonium chromium salicylate corresponding to 5.3 parts of chromium oxide until the formation of the com plex dyestuff has completed. The deep bluishviolet solution is separated by filtration while hot from the difficultly soluble product containing chromium. By addition of sodium chloride to the filtrate the new dyestufi is obtained. It dyes wool from an acid bath in blue-violet uniform shades of very good iastness properties.

Example 3 53.4 parts of the dyestuff obtainable from diazotised 4-chloraminophenol and 1:8-naphthol sulfonic acid-3-sulfanilide are boiled in 3000 parts of water with 300 parts of a solution of ammonium chromium salicylate' corresponding to 20 parts of chromium oxide until a test specimen has been proved fast to acids and to alkalis. Then there is hot filtered in order to separate the diificultly soluble, chromium-containing portion and the dyestuff is precipitated from the filtrate by addition of sodium chloride; thus giving a violet-blue powder. It dyes wool from an acid bath in pure blue-violet shades of very good fastness properties.

Example 4 56.6 parts of the sodium salt of the dyestuif from diazotised 5-nitroaminophenol and 1:8- naphthol sulfonic acid-3-sulfanilide are'boiled for 50 hours under reflux and under stirrin in 1000 parts of water with 600 parts of a solution obtainable 4 of ammonium chromium salicylate corresponding to 22.8 parts of chromium oxide. Thus, the dyestuff being first completely undissolved goes in solution to a deep blue coloration while forming the complex compound. The dyestuff containing chromium is precipitated by addition of sodium chloride. It dyes wool from an acid bath in greenish-blue shades of a pleasing even color.

Example 5 45.6 parts of the monosodium salt of the dyestuff obtainable from diazotise'd 4:6-dinitro- 2-amino-1-phenol and 1-hydroxynaphthalene-5- sulfonic acid are dissolved in 700 parts of water, boiled for some hours with the chromium complex compound obtainable by neutralising with sodium carbonate a hot solution of 70.6 parts of sodium- 2 -hydroxy 5 sulfethylanilidebenzoatc and of 8.4 parts of chromium oxide in form of chromium fluoride. The deep black solution is then treated with sodium chloride, whereby the new chromium-containing dyestuff is precipitated in a resinous form. It forms on drying a black powder. When applied from an acid bath this dyestuif gives black shades of very good iastness properties in the moist state and oi a very good light-fastness.

Example 6 20.8 parts of the disodium salt of the dyestuii obtainable from diazotised l-aminonaphthalene- 4-sulfonic acid and 2-hydroxybenzoic acid are heated under reflux to boiling for 2 hours in 250 parts of water with parts of a solution of ammonium chromium salicylate corresponding to 4.2 parts of chromium oxide. Thus, a brownyellow solution is formed which, by a treatment with concentrated..-hydrochloric acid, becomes violet. The-solution is evaporated in va-cuo at a raised temperature. There remains a brownyellow powder dyeing Wool from an acid bath in golden-yellow shades ofv good uniformity.

Example 7 62.4 parts of the disodium salt of the dyestufi from diazotised l-aminonaphthalene- 5-sulfonic acid and Z-hydroxybenzoic acid are dissolved in 750 parts of hot Water, heated for a short time to boiling with a solution of ammonium chromium salicylate corresponding to 126 parts of chromium oxide; then the chromiumcontaining. dyestuff isisolated by addition of sodium chloride. It dyes wool from an acid bath in clear golden-yellow shades of good fastness to light.

Example 8 12 parts of the dyestu'fi obtainable from diazotised 4-nitro-2-amino-l-phenol 6 sulfonic acid and 4-isobutyl-2-methyl-lpheno1 are stirred with 300 parts of water and 72 parts of a solution of ammonium chromium salicylate corresponding to 2.73 parts of chromium oxide and heated during 3 hours to C. in a closed vessel. The chromed dyestuff, which has partly precipitated after cooling of the reaction mass, is completely precipitated by addition of sodium chloride. The chromium-containing dyestuff thus obtained dyes wool, from an acid bath in full reddish-brown shades of excellent fastness properties.

7 Example 9 38 parts of the disodium salt of the dyestuif obtainable from diazotised l-aminobenzene-3- sulfonic acid and 1-methyl-2-hydroxybenzene-3- carboxylic acid are dissolved in 600 parts of hot 362B parts oi the :disodium "salt of the dyestu'fi obtainable from diazotised l-aminribenzenmsulfonic acid and, Z-hydroxybenzene-i-carboxylic acid .are dissolved .in 500 martsof hot water and, after addition .of .24osparts .of .a solution =of :ammonium .chromiumsalicylate vcorrespo-nding .to-B .-1 parts of chromium .oxide, boiled during -5 .hours. The deep yellow solution of the resulting chromium complex .dyestufi .is treated with 200 rparts of sodium chloride .and .35 parts of concentrated hydrochloric .acid. The precipitated dyestuff .is

filtered offanddried. Thus abright brown powder obtained which dyes wool from a aformic acid bath in clear yellow .shades of very good evennessand o'fgood 'fastnessproperties.

Example 1 1 159;? parts of themon'osodium salt of the azo dyestufi obtainable from diazotised '5-n'itro-2- aminophenol-(l) andl-naphthdl-B-sultoriic acid,- 3-sulfonic acid-4-methoxyanilide (the coupling component is obtained by 'condensation of 1:8- naphthsultone iiesulfochloride with .l-amino-A- methoXy-henzene and Joy subsequent alkaline .saponification of the condensation .product') are stirred .in 150 ,parts of .hot water, .treated with a solution of ammonium chromium salicylate corresponding to .2213 ,parts of chromium and st'nredatiboiling temperature under refiuxcduring 24lhours. .Thus the dyestuff salt Ibeingat .the'beginning of the .chroming nearly completely undissolved .goes into solution to a deeplblue coloration. This solution, which does .not show any change .of coloration .on mixing it with dilute .alkali .or mineral acid, is hot Qfiltered and the complex .dyestufi is separated .irom (the solution Tby addition of sodiumchloridelthusproducing adark blue powder. The new chromium-containing dyestuff is easily water-soluble and dyes wool from a .formic acid :bath .in clear greenish-blue shades of good evenness. .Th'e :dyeings EPQSSGSS :generally good fastness properties .in the moist .state as wellas *a good .fastness .toirubbingand tolight.

. Exam-pie 12 59.9 parts of the disodium .salt of the .dyestiifi obtainable from carboxylicacid and l-naphthOl-S-sulfonic.acid 3 sulfethylanilide are stirred in '100'0.par.ts of water and, after .addition of 2140 parts of .a .solution of ammonium chromium salicylate corresponding to 9.1 .parts of chromium oxide, boiled under stirring andunder reflux until 'thedyestu'ff has been transformed into the complex form, .this being the case after '15 to 20 hours. The deep red so'lu tion is hotfiltered in order to eliminate some "insoluble, chromium-containing hy-products; then the chromium complexdyestuff is isolated' bysa'turation with sodium-chloride. lt constitutes a fter drying, a"darkwine red powder' which is very-well soluble in water. Fromafor-mic acid bath i tdyes diazoltised '2-aminob'enzene-l 6 wool in pure, wine-red shades :of :complete evenmess. The :dyeing-s are -distinguished by good fastness properties (to tulling, perspiration :and rubbing as well as by .a very :good light-fastness.

*Emample 1-3 58:3;parts of-the sodium-salt of the-dyestuff obtainable irom diazotised 5-.nitr0-2-aminophenol and 1:8-naphthol sulfonic acid-3-su1fethyl phenylamide are-suspended .in 2.000 parts of water :and heated to :boiling ior .15 hours with v24.0 parts of .solution of-ammonium chromium salicylate corresponding'to 9. 1 .partsof chromiumoxide. Thus. by this :chroming a=deep.-blues01ution is produced. The {new chromium-containing dyestufl is isolated .in the -.usual manner :by precipitation with SOdill'IIlzGhlOI-idfi. .lit dyes wool =from-an acid bath in greenish-blue shades.

Example 14 59.5 .parts of -the dyestuff obtainable from .diazotised fien-itro-a-methyli amino-l-phenol and l :8 enaphthol .sulfonic acid-3-sulfethylanilide are dissolved in.1000 parts of hot water and, after addition 01-240 ;parts of a solution of ammonium chromium salicylate corresponding to9.1 parts of chromium =oxide, boiled .for several hours. Ifhe deep .bluersolution-of the complex dyestuff is filtered .and the .dyestuff is precipitated from the filtrate by addition of sodium chloride. After drying the .dyestuff constitutes a dark blue powder. It dyes wool from an acid bath in navy-blue shades of very goodliglit-fas'tness and good fastnees properties in the moist state.

Example 15 151:8 .partsof the dyestuff obtainable from diazotised AE-chloro-l5enitroe2-amino laphenol and 1 iS-naphthol sulfonic acid-B-sulfethylanilide are suspended .in 1500 parts-of hot water and stirred trboiling temperature duringbhours witha solution .of :ammonium chromium salicylate corresponding to .9.-1 parts of chromium oxide. Thus, under-formation of thecomplex-compound, a deep blue solution is formed. which, after cooling, is

treated with :sodium chloride until all the dyestuff .has precipitated. The dark blue-violet powder is .filtered and dried. 'I-t dyes wool from an acid bath in flowery tblueshades-of very good fastness to light and tor-ubb'in-g.

Example 1 6 5917 ,parts of thesodium salt of the dyestufi' .obe tainalole .from .diazoltised 5-nitro-4-methyl2- amino- 1- .'p'henol and .lzB-naphthol .sulfonic .acid- 3-.sulfethylani-lide aresuspended in 1200 parts of hot water .and then Iboiled during 3 .hours with 250 parts of a solution of ammonium chromium salicylate corresponding 13053.36 parts of chromium oxide. At the beginning of the chroming there-is rapi'd-ly'iformed a "deep blue solution, from whichthe complexdyestuff finally begins to crystallise. "Then, the whole is cooledand the blueblack, crystalline dyestufi is filtered by "suction and "dried at an elevated temperature. The chromium-containing dyestuff dyes wool from an acid bath in flowery reddish-blue shades 'of high evenness and of very good light-fastness.

Example 1 7 61:3 parts of the dyestifif obtainable f-rom 'diaz'otised '6 riitro 4-chloro 2-amino-l-phenol and l hydroxy-naphthalene-S-sdlfonio acid ethyl-(3'- sullonic ac'i'd phenyl) -amide are heated to boilirig 'f01-*8 hours in 1000 parts of water with 600 parts of a solution of ammonium chromium saliwith the calculated quantity of caustic soda lye.

Example 18 32.2 parts of the dyestuif obtainable from diazotised 1-aminobenzene-3-sulfonic acid and 2- hydroxybenzoic acid are dissolved in form of the ammonium salt in 200 parts of water and, under stirring, evaporated on the water-bath with 240 parts of a solution of ammonium chromium salicylate corresponding to 9.1 parts of chromium oxide. The remaining viscous mass is dried in vacuo at an elevated temperature. The chromium-containing dyestufi being an olive-yellow powder dyes wool from an acid bath in greenishyellow clear shades of very good evenness.

Example 19 62.8 parts of the sodium salt of the dyestuff obtainable from diazotised -nitro-2-aminophenol and 1:8-naphthol sulfonic acid-3-sulfonic acidethyl-(3-nitrophenyl) -amide are dissolved in 1500 parts of hot water, treated with 240 parts of a solution of ammonium chromium salicylate corresponding to 9.1 parts of chromium oxide and then heated to boiling. After a short time the dyestufi salt has been transformed into the complex form thus giving a deep blue coloration which, on addition of diluted mineral acid, undergoes no further change. Then the solution is treated with sodium chloride and the dyestuif precipitated as blue-black powder is filtered by suction and dried. It dyes wool from an acid bath in greenish-grey shades.

The 1:8-naphthol sulfonic acid-3-sulfonic acid-ethyl-(3-nitrophenyl)-amide is made in the following manner: 1-ethylamino-3-nitrobenzene is condensed in anhydrous pyridine with naphthsultone-3-sulfochloride and the so-obtained naphthsultone-S-sulfonic acid-ethyl-(3'- nitrophenyl) -amide is saponified with the calculated quantity of hot dilute caustic soda lye.

Example 20 11.9 parts of the sodium salt of the dyestuff obtainable from diazotised 5-nitro-2-amino-1-phenol and 1:8-naphthol sulfonic acid-3-sulfonic acid-ethyl-(2'-methylphenyl) -amide are suspended in 150 parts of water and treated with 53 parts of a solution of ammonium chromium salicylate corresponding to 1.82 parts of chromium oxide. Thus a bronzy mass is formed which is now heated to boiling under reflux and under stirring. After some hours the complex formation is complete. The new chromium complex dyestufl' precipitates almost completely on cooling the resulting solution. The precipitate is then filtered and dried. From an acid bath the dyestuff gives flowery blue shades of good evenness. r

Example 21 12.2 parts of the sodium salt of the dyestuff obtainable from diazotized 5-nitro-4-methyl-2- amino-l-phenol and 1:8-naphtho1 sulfonic acid- 3-sulfonic acid ethyl (2'-methylphenyl) -amide are partly dissolved in 150 parts Of hot water and stirred at -100 C. under reflux for 15 hours after having added 53 parts of a solution of ammonium chromium salicylate corresponding to 1.82 parts of chromium oxide. The formed chromium complex dyestuif, which partly separates already in the heat in a beautiful crystalline form, is completely precipitated by addition of sodium chloride and isolated. It dyes wool from an acid bath in beautiful, fiery, blue shades of good evenness.

Example 22 57.5 parts of the soduim salt of the dyestuiT obtainable from diazotised 5 nitro 2 amino-1- phenol and 1:8-naphtho1 sulfonic acid-S-sulfonicacid-methylphenyl amide are dissolved in 750 parts of hot water and treated with 240 parts of a solution of ammonium chromium salicylate corresponding to 9.1 parts of chromium oxide. The mixture is heated to boiling and stirred under reflux until a clear, deep blue solution has been formed, which undergoes no further change in coloration upon addition of dilute mineral acid. The solution is treated with sodium chloride and the complex dyestuif precipitated in a crystalline form is filtered off and dried. The low chromium-containing dyestuff dyes wool from an acid bath in flowery blue shades of very good fastness to fulling and perspiration.

Example 23 589 parts of the dyestuff obtainable from diazotised 5-nitro-4-methyl-2-amino-1-phenol and 1:8-naphthol sulfonic acid-S-sulfonic acid-methylphenyl amide are stirred in 750 parts of Water and, after addition of 240 parts of a solution of ammonium chromium salicylate, heated to boiling. By the chroming a clear, deep blue solution is formed after a short time, the same being, when still not, treated with sodium chloride. After cooling the powdery dyestufi thus precipitated is filtered by suction and dried at elevated temperature. The new chromium containing dyestuif dyes wool from an acid bath in very uniform, flowery, blue shades of good fastness properties to fulling and perspiration.

Example 24 57.5 parts of the sodium salt of the dyestuff obtainable from diazotised 5 nitro 2 amino-1- phenol and 1:8-naphthol sulfonic acid-5-sulfonicacid-methylphenyl-amide are boiled for 20 hours under reflux and under stirring in 1000 parts of a solution of ammonium chromium salicylate corresponding to 9.1 parts of chromium oxide. Thus, a deep blue solution is formed, from which the complex dy'estuff partly crystallises already in thehot. In order to isolate the dyestuff the solution is treated with sodium chloride and the dyestuff thus precipitated as a dark blue powder is filtered by suction and dried. It dyes Wool from an acid bath in greenish-grey shades of excellent fastness properties to fulling and to perspiration. v

. The 1 :8-naphthol sulfonic acid 5 sulfonic acid-methyl phenyl-amide is produced by condensation of methylphenylamine with 1:8- naphthsultone5-sulfochloride and by alkaline saponification of the obtained condensation prodage-aces x I uct. The '1:-8-'naphthsulto'ne -5'- sulfonic "acid chloride is obtained by heating 1 mole ofthe sodium salt of the 1:8-naphthsultone-5-sulfonic acid with 1 mole f phosphorus .p'en'tachloride.

Example 25 57.1 parts of the sodium salt of the dyestuff obtainable from diazotised -nitro-2-amino-1- acid-4'-methylphenyl ester are dissolved in 1000 phenol and 1:8-naphthol sulfonic acid-3-sulfonic parts of hot water and, after heatin to 100 0., treated with 20.0 partsof a solution of ammonium chromium salicylate. Thus :a' bronzing precipitate is separated which, on :further stirring at 100 C., rapidly :dissolves to a deep blue solution. it is treated with sodium chloride After 5 hours and the precipitated complex dyestuff is'filtered. The new dyestuii dyes wool from an acid bath in navy-blue shadesof very good light-fastness and good fastnessto potting.

The 1:8-naphthol sulfonicacid-3-sulfonic acid- 4-methylphenyl. ester is produced by condensation of 1:8-naphthsultone 3-sulfoni'c acid chloride with 4-methyl-l-liydroxybenzene and by saponification of the condensation product with the calculated quantity of sodium carbonate.

Example 27 29.3 parts of the sodium salt of the dyestuff obtainable from diazotised 5-nitro-4-methyl-2- amino-l-phenol and -1 :8-naphthol sulfonic acid- 3-sulfonic acidl' methylphenyl ester are suspended :in '500 parts 0f water and, aftera'ddition of 200'parts 'ofa solution of ammoniumchromium salicylate corresponding to 8-.3 parts (if-chromium oxide, boiled un de'rreflux andunder stirring during 60 hours. Bythe-chroming a blue-black powder is formed which is sucked off after cooling and dried. These-obtained chromium-containing dyestuff dyes .wool fromanacidbath in navyblue, flowery shades o'f'very good light-fastness andioflgo'od evenness.

Example 28 i 4.89 parts of the dyestuff obtainable from diazotised '6-nitro-4-amyl-2-amino-l-phenol and 3'-sulfophenyl-3-methyl-5-pyrazolone are .sus-

pended in .75 ipartsof water and, after additionof 24.partsof asolutionofamm'on'ium chromium salicylate corresponding to -0.'-91-part of chromium oxide; stirred for-some hours at 90--100?%C. Thus, a gelatinous solution. is obtained, which is stabel to dilute acid vand -whicl i 'i'sevaporateiil 'to dryness in'Z-vacuo atelevated temperature. {The new chromium-containing d-yestufira red peweeg;

dyes wool from an acid bathin clear, red-shades of very, good fastness properties to light, fulling and to perspiration.

Instead of the compleic chromium compounds A used in the above examples for the chrom'ing, of

10 course also other o-hydroxycarboxylic acid compounds of "the benzene series mentioned in the general part of this specification maybeused'; in view of economical reasons the simplest and cheapest compoundsw'ill especially be used.

Vi/hatwe claimis:

1. process for rchroming a chromable monoazo 'dyestuff containing one sulfonic acid group and two aromatic nuclei selected 'fromthe class consisting of nuclei of the benzene and naphthalene series, which comprises chroming the said chromable monoazo dyestuffwitha complex chromium compound of an o-hydroxybenzo'ic acid in such proportions that at least one atom of chromium "is present for each chromable .group of said chromable compound.

2. A process forchroming a chromable monoazo dyestuff containing one sulfonic acid group and two aromatic nuclei selected from the class consisting of :nuclei of the benzene and naphthalene series, which comprises "chroming the said dyestufi with the complex chromium compound of salicylic 'acidin such proportions that at least one atom of chromium is present for each chromable group of said chromable dyestufi.

3. A process for chroming a chromable monoazo dyestui'f containing one sulfonic acid group, two aromatic nuclei selected from the class consisting of nuclei'of the benzene and naphthalene series, and a hydroxy .group in at least one of the oand o-p.ositions to the azo bridge, which comprises chromingthe said dyestufi with a complex chromium compound of an o-hydroxybenzoic acid in such proportions that atleast one atom of chromium is present 'for each chromable group of said chromable dyestufi.

4. A process 'for chroming a chromable monoazo dyestuif containing one sulfonic acid group, two aromatic'nuclei selected'from the .class consisting of the benzene and naphthalene series,

and one o=hydroxy-carboxy-grouping, Which comprises chroming the said dyestuff with a complex chromium compound "of an 'o-hydroxybenzoi'c-a'cid insuch proportions that at least-one atom-'of chromiumis present for 'each 'chromaole group -of said-chromable dyestuiif.

5. A process for chroming a chromable monoazodyes'tu'ff containing one sulfonicacid group,

two :aromatic nuclei selec'tedfrom theclass-con- -sisting of nuclei oi the benzene and naphthalene series, and a carboxy and a hydroxy group *in o:-'o'--position ito the azo bridge, which comprises chroming the said dyestuff with a complex'chromium :compoun'd of-an o-hydroxybenzoic acid in L-such proportions that at least one atomofchromium is present for each chromable groups "of said chromable dyestufi.

6. A process for chroming a chromable monoazo dyestuff containing one sulfonic acid group,

two aromatic nuclei selected from .the classconsisting of nuclei ofthe benzene and naphthalene series, and a hydroxy group in at least one of the oand o'-positi0ns to the azo bridge, which comprises chroming the said dyestufi with a complex chromium compound of salicylic acid in such proportions that at least one atom of chromium is present for eachchromable group of said cromable dyestuff;

'7. A process for chroniing a chromable mono- -azo dyestufi .containingone sulfonic acid group,

two aromatic nuclei selected from the'c'lass consisting, of .the benzene and naphthalene series, and one, .0hydroxy-carboxy-grouping, which compriseschroming the said dyestuff with-a complex chromium compound of salicylic acid in such proportions that at least one atom of chromium is present for each chromable group of said chromable dyestufi.

8. A process for chroming a chromable monoazo dyestuir containing one sulfonic acid group, two aromatic nuclei selected from the class consisting of nuclei of the benzene and naphthalene III-CH3 which comprises chroming the said dyestuiT with the complex chromium compound of salicylic acid in such proportion that at least one atom of chromium is present for each chromable group of said dyestufi.

10. A process for chroming the dyestuff of the formula Hols cooH which comprises chroming the said dyestufl with the complex chromium compound of salicylic acid in such proportion that at least one atom of chromium is present for each chromable group of said dyestuif.

11. A chromed chromable dyestuff containing one sulfonic acid group and two aromatic nuclei selected from the class consisting of nuclei of the benzene and naphthalene series, chromed by means of a complex chromium compound of an o-hydroxy-benzoic acid, and containing at least one atom of chromium for each chromable group of said dyestuff.

12. The chromed chromable dyestuff of the formula being chromed by means of the complex chromium compound of salicylic acid and containing at least one atom of chromium for each chromable group of said dyestufi, and being an easily soluble blue powder dyeing wool in even blue shades.

12 1.3. The chromed chromable dyestufi of the formula being chromed by means of the complex chromium compound of salicylic acid and containing at least one atom of chromium for each chromable group of said dyestufi, being a brownishyellow powder, easily soluble in water and dyeing wool in bright greenish-yellow shades.

14. A process for chroming the dyestuif of the formula OH SOaH which comprises chroming the said dyestuff with the complex chromium compound of salicylic acid in such proportion that at least one atom of chromium is present for each chromable group of said dyestufi.

15. The chromed chromable dyestuif of the formula COOH OH SOaH being chromed by means of the complex chromium compound of salicylic acid and containing at least one atom of chromium for each chromable group of said 'dyestuif, being a dark wine-red powder, easily soluble in water and. dyeing animal fibres in light-fast pure wine-red shades.

ACl-IILLE CONZETTI. GUIDO SCHETTY. OTTO SCHMID;

REFERENCES CITED The following references are of record in the file of this patent:

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